Many of you probably know "xcalib -i -invert" on linux inverts the screen by switching the colour tables for the display. So the whole of X is inverted.

Try it now, run again to switch back. Its trippy, But good for not being blinded late night word processing or PDF reading.

I have thought the same would be nice for the N900, command line to run as a hook from maybe the app that runs things on camera button presses. Anyone tried? Is it possible?